Nitriles can be prepared by various techniques that result in the co-formation, or subsequent formation, of ketone impurities having boiling points so similar to the boiling points of the nitriles that simple distillation is not an effective way of purifying them. Among the nitrile syntheses that result in such impure nitriles are:
(A) the nucleophilic substitution reactions of U.S. Pat. No. 4,370,278 (Stahly et al. I); copending applications Ser. No. 452,518 (Stahly et al. II), Ser. No. 452,615 (Stahly), and Ser. No. 452,618 (Stahly et al. III), all filed Dec. 23, 1982; Ser. No. 474,138 (Stahly et al. IV), filed Mar. 10, 1983; and Ser. Nos. 487,039 (Lilje I) and 487,038 (Lilje II), both filed Apr. 21, 1983, and
(B) the Gomberg and pseudo-Gomberg processes disclosed in Stahly et al. I and copending applications Ser. Nos. 488,192 (Ramachandran I) and 488,068 (Ramachandran II), both filed Apr. 25, 1983, and Ser. No. 523,161 (Davidson) and Ser. No. 523,450 (Herndon), both filed Aug. 15, 1983.